I ALMOST DON'T RECOGNIZE Cecilia Bartoli as she comes bouncing into the Salzburg Felsenreitschule in August, wearing simple pink-and-black street clothes and looking as if she just went for a jog along the Salzach. Disarmingly generous and down to earth, Bartoli shakes my hand warmly before turning to look at the graffiti-covered set for West Side Story. In a few days, she’ll be on the stage of the Felsenreitschule, one of Salzburg’s principal performance venues, singing Bernstein’s Maria—a role she added to her repertoire during the 2016 Salzburg Whitsun Festival.

Since 2012, Bartoli has served as artistic director of the Whitsun Festival, which takes place in late spring, over Pentecost weekend. Since taking up the post, Bartoli—one of the opera world’s few unquestioned superstars—has given the festival renewed international prominence. The May 2016 Whitsun mounting of West Side Story, which also gathered maestro Gustavo Dudamel and his Simon Bolivar Orchestra, may well have been the most sought-after ticket in Europe.

While West Side Story’s Whitsun and summer runs sold out in a flash, Philip William McKinley’s grim, industrial production received many scathing reviews. McKinley’s concept, developed with Bartoli’s blessing if not her direct input, was to frame the entire show as the flashback of a middle-aged Maria who has been living a sad, solitary existence in the decades since Tony’s death. The bright-eyed Maria, fresh off the boat from Puerto Rico, was portrayed by a young actress, while Bartoli haunted the stage of her reveries, getting caught up in them whenever the music summoned her. The double Maria strategy seemed to work two ways—by insisting on Maria’s youth and sparing Bartoli a lot of English dialogue. More controversial by far, however, was McKinley’s decision to have Bartoli’s Maria throw herself under a train at the end of the evening. Bernstein and Sondheim had considered a faithful Romeo and Juliet ending but decided that three corpses were enough. McKinley may have felt he was honoring the creators’ original intentions (including Shakespeare’s), but apparently the estates of Bernstein and Arthur Laurents (who wrote the book) were less than pleased. For her part, Bartoli defends her director’s decision: “He had such a strong argument, and an interesting one. For me, it brings a new dimension and depth in the character of Maria. What happened to Maria after Tony died? Fans of West Side Story are still talking about this.”

PREPARATIONS FOR A WEST SIDE STORYrehearsal are under way as Bartoli and I talk in the seats of the Felsenreitschule. Bartoli is eager to talk about one of her earlier outings at Whitsun, a riveting Norma from 2013 that signaled the mezzo-soprano’s bold ambitions for the festival. A week ago, Moshe Leiser and Patrice Caurier’s intense production, set in occupied France during World War II, traveled to the Edinburgh Festival, where Bartoli made her festival debut. The performances were handily sold out, and the reaction, she tells me, was tremendous. “People already started with the standing ovation at the end of the first act, after the terzetto, this trio which is very intense,” Bartoli says animatedly, the excitement of the performance still fresh with her.

Edinburgh was only the latest stop on a Norma tour that has included Paris, Zurich and Baden-Baden. “It was one of the biggest successes I’ve had since I’m artistic director,” she says about the performance, which used a new critical edition. “When we did this in 2013 it was a revelation for all of us, because it was a new vision musically and a new vision onstage.” Bartoli says that for the first time in the modern age, Bellini’s score was performed at A=430 rather than A=440 (the original, lower tuning). Launching this “new vision” here in Salzburg brought renewed attention to the Whitsun Festival and acclaim for Bartoli’s artistic direction.

That Whitsun production of Norma, which formed the basis for the acclaimed Decca recording that followed, was revived that year and again two years later at the Salzburg summer festival—an example of Bartoli’s innovative desire to create links between the two festivals. “Because we have five to six weeks of rehearsals for new productions [at Whitsun], I found it quite frustrating to only do two performances. It’s such a lot of work. Look!” She indicates the gargantuan West Side Story set in front of us. “Can you imagine this massive production lasting for just two performances? We needed to give ourselves the chance to perform and grow. With only two performances—the premiere and closing night—we didn’t have that chance.”

BARTOLI IS THE FIRST WOMAN to serve as an artistic director at Salzburg, and she doesn’t take the assignment lightly. “It’s clear that we’re talking about the world’s most important festival for classical music, and we have a big responsibility. If you consider that my predecessor was Maestro Muti, and that before him we had Karajan, we do have a responsibility to continue this wonderful tradition and keep this wonderful festival at a very high level.” As a singer, Bartoli came to the job with a different skill set than either predecessor she mentioned. “At first I thought, ‘Do they really want me?’ But I took it as a kind of challenge. I’ve done a lot of different kinds of projects during my career, from Baroque music to pre-Romantic music. When I started at Salzburg, I decided to focus on a very interesting woman, Cleopatra—to give a feminine touch to the festival,” she says with a sparkling laugh.

Bartoli’s creativity, star power and charisma have helped Whitsun’s ticket sales reach an all-time high. She says the festival is drawing a younger crowd than ever. “When we started with Cesare, what we saw was that it was possible to attract new audiences to Salzburg, including a younger audience,” she says. “Clearly, this is the case with West Side Story, but I realized something was going on from the very beginning.” Bartoli describes this as a gain from her thematic approach to programming the festival: West Side Story was the centerpiece of a season devoted to Romeo and Juliet. Some might have been surprised to encounter a Broadway musical in Salzburg. “It’s true that this is a festival for classical music, but for me West Side Story is one of the most geniale classical pieces. I thought, ‘Why can the music of [Wolfgang] Rihm be performed here but not the music of Bernstein?’ For me, that makes no sense. For me, there is good music and bad music. And without a doubt what we’re talking about here is not good music—we’re talking about fantastic music. Period.”

Bartoli says the condensed format of the Whitsun Festival lends itself to thematic approaches. “Here it’s possible to have a tema, because the Whitsun Festival is quite short, and there is a kind of red thread you can follow, which would be much more difficult to pull off in the summer, with so many performances. I feel that this allows the audience to participate in a different way.” Bartoli’s themes are often poetic—the current one is “Joy of Grief”—and Scottish Romanticism looms large in the upcoming festival, which includes Handel’s Ariodante, in a production by Christof Loy, and a concert version of Rossini’s Donna del Lago, which will reunite Bartoli with her West Side Story costar, American tenor Norman Reinhardt.

“This is another new step for me, because I’ve done a lot of Baroque music, and I’m a big fan of Handel operas, especially his London period. I’ve sung Alcina, which is definitely one of my favorite operas. But Ariodante is another great one, and I’m going to be playing a male character for the first time in Salzburg. I’m definitely looking forward,” she says. I ask if she’s ever sung La Donna del Lago, and she shakes her head. The Walter Scott-inspired melodramma will be Bartoli’s second role debut in the space of forty-eight hours.

THE REST OF BARTOLI'S programming for Whitsun 2017 is equally ambitious and eclectic. “It’s short but very intense,” Bartoli says, with good reason. Between June 2 and June 5, 2017, the Handel and Rossini scores will be heard alongside a concert by the Orchestra dell’Accademia Nazionale di Santa Cecilia, with Antonio Pappano pacing Bryn Terfel and Tatiana Serjan in scenes from Verdi’s Macbeth and Wagner’s Fliegende Holländer, the Ballet of the Mariinsky Theatre performing La Sylphide (Bartoli can also be credited with bringing ballet back to Salzburg after an absence of many years) and—breaking with the Scots theme—an anniversary concert for Anne-Sophie Mutter, who made her Whitsun debut forty years ago at the age of thirteen.

Bartoli’s knack for unexpected choices—certainly familiar to anyone who has followed the mezzo’s work onstage and in the recording studio—has allowed her to settle easily into her new role. “I think that it works so well because I’m an age now, with my experience and everything, when I can give back all that I’ve received but still with energy and passion for making music,” she says with a smile.

Whichever side of the curtain she’s on, Bartoli knows the focus belongs first and foremost on the music. “I’ve been singing now for thirty years. I’ve had a lot of experience with different directors, conductors and orchestras and singers. What works is finding directors who really respect and believe in the power of music—music as a source of inspiration, and not just what’s in the libretto. It’s exciting, and I’m still learning.”

When I ask whether running the festival has opened her eyes to the complex world of music administration, she answers emphatically, “Not just my eyes. As a singer, I had to take care of my voice, of my instrument. But now, as artistic director, I have to take care of everyone. I realize that every artist has such different kinds of needs and how important it is to find the right kind of harmony, the right kind of stream for the whole team to find good solutions. It’s difficult to make everybody happy, but as long as everyone is serving the composer, the music and the production, we’re all working for the same goal.” How does it feel to be the captain of this team? “I’m like a big mama now!” She laughs.

AT THIS POINT, Philip William McKinley, West Side Story’s director, arrives to tell Bartoli that he needs her onstage and in costume in seven minutes. In our remaining moments, I try to get her to divulge her future plans for the festival. She eyes me playfully. “2018 is definitely interesting,” she says, “but I always like to keep things a surprise.”

In 2014, just two years into Bartoli’s tenure, the Salzburg Festival renewed her contract until 2021. When I bring this up, she sounds touched both that the festival asked her to stay and that her directorship has been considered a success. So, what is the secret to that success?

“My secret?” She seems lost in thought for several moments before answering. “You never really know. It’s like the secret for a nice ragù. Very good, high-quality ingredients and a lot of passion and love for your profession.” And with that, she runs out of the theater to get into costume.

A. J. Goldmann writes about arts and culture for The Wall Street Journal and The Forward.